Postharvest Biology and Technology 51 (2009) 200–205 Contents lists available at ScienceDirect Postharvest Biology and Technology journal homepage: www.elsevier.com/locate/postharvbio Development of a carbon-heat hybrid ethylene scrubber for fresh horticultural produce storage purposes Domingo Martínez-Romero a,∗ , Fabián Guillén a , Salvador Castillo a , Pedro Javier Zapata a , María Serrano b , Daniel Valero a a Department of Food Technology, EPSO, University Miguel Hernández, Ctra. Beniel km. 3.2, 03312 Orihuela, Alicante, Spain b Department of Applied Biology, EPSO, University Miguel Hernández, Ctra. Beniel km. 3.2, 03312 Orihuela, Alicante, Spain article info Article history: Received 5 May 2008 Accepted 19 July 2008 Keywords: Ethylene removal Activated carbon Palladium Catalyst Carbon dioxide Postharvest storage areas abstract A scrubber to remove ethylene continuously from stored environments was developed. The device com- prised a cartridge heater tightly joined to the activated carbon–1% Pd. The application of heat pulses led to an increase in ethylene oxidation and to auto-regeneration of the activated carbon. The efficacy of ethylene removal was higher with the number of heat pulses. Several combinations of exogenous ethy- lene concentrations and heater core temperatures (100–325 ◦ C) of the device were assayed to determine their effectiveness in removing ethylene from the storage area. The results indicated that increasing the heater temperature led to enhanced percentages of eliminated ethylene but also increased CO 2 concentra- tions. This CO 2 could come from the activated carbon due to its breakthrough. Thus, temperatures ranging between 150 and 200 ◦ C eliminated 96–99% of ethylene, with low CO 2 accumulation (0.10–0.18kPa) and without affecting the temperature of the storage environment. Thus, this device might be a promising tool for scrubbing ethylene from storage areas for fresh horticultural produce in which ethylene can induce detrimental effects. © 2008 Elsevier B.V. All rights reserved. 1. Introduction Ethylene in many situations induces detrimental effects in fruit and vegetables when it is produced and accumulates through the postharvest chain (Martínez-Romero et al., 2007). There are many reports describing the negative effects of atmospheric ethylene and its relationship with storage life, where concentrations higher than 0.10 LL -1 can induce important quality loss in a wide range of commodities (Wills and Warton, 2000; Wills et al., 2001) leading to a reduction in shelf-life by acceleration of ripening and senes- cence processes. In this sense, it has been a goal in postharvest technology to achieve effective control of ethylene. Much work has been done through the inhibition of ethylene biosynthesis (Paull and Chen, 2000; Valero et al., 2002) or at the action level (Martínez- Romero et al., 2003; Watkins, 2008). However, there are many situations in which considerable ethylene accumulation occurs along the food chain, such as inside packages, storage chambers, during transportation and in domestic refrigerators. This external ethylene comes from different sources, such as internal combustion engines, pollutants released in the atmosphere, normal emission from plant organs and fungal metabolism (Chang and Bleecker, ∗ Corresponding author. E-mail address: dmromero@umh.es (D. Martínez-Romero). 2004). Adequate fresh air ventilation of storage areas has been clas- sically used as an effective way of removing ethylene, although this procedure has an enormous disadvantage in terms of losses of energy (by increasing the temperature of cold storage rooms) and humidity, and is not practicable in controlled atmosphere stor- age. One tool for ethylene removal has been the use of adsorbers, activated carbon being one of the most tested (Choi et al., 2003; Bailén et al., 2006), although ethylene elimination was not totally achieved. On the other hand, the use of some catalysts (Pd, Ti, Cu, Rh and Co) have also been shown to be effective in ethylene removal by oxidising ethylene to CO 2 +H 2 O(Conte et al., 1992; Maneerat et al., 2003). Thus, better results could be expected through the combina- tion of adsorbent and catalyst, as has been recently reported with the use of activated carbon and Pd (Bailén et al., 2007). However this system had several disadvantages: the large, necessary mass of adsorbent, saturation of the system (due to adsorption of ethy- lene and other environmental gases) and subsequent loss of efficacy over time, the reposition of the material, with the most important derived from non-continuous operation since regeneration of the adsorbent is very necessary. Taking into account these premises, we hypothesised that the application of heat to the adsorbent–catalyst system could induce two effects: (a) an increase in the rate of the ethylene removal, (b) elimination of the gases deposited on the activated carbon, 0925-5214/$ – see front matter © 2008 Elsevier B.V. All rights reserved. doi:10.1016/j.postharvbio.2008.07.013